1. Technical Filed of the Invention
The present invention relates to a functional device comprising a photoelectric conversion layer and a luminescent layer deposited over a substrate and method for producing same.
2. Description of the Related Art
In recent years, devices comprising an organic material represented by organic luminescent device have made a remarkable progress. The production of organic EL displays which represent the organic luminescent device has been succeeded in practical utilization. Although the production of photoelectric conversion devices comprising an organic semiconductor has never been succeeded in manufacturing, these devices have made a remarkable progress in recent years and are likely to overcome the following problems with the related art imaging devices.
In the related art CCD type solid imaging devices or CMOS type solid imaging devices, a number of photoelectric conversion devices (photodiode) which are light-receiving portions and a signal readout circuit for reading a photoelectric conversion signal obtained in these photoelectric conversion devices to the exterior are formed on the surface of a semiconductor substrate. The signal readout circuit is formed by a charge transfer circuit and a transfer electrode if the solid imaging device is of CCD type or formed by an MOS transistor circuit and a signal wiring if the solid imaging device is of CMOS type.
Accordingly, the related art solid imaging device is disadvantageous in that a number of light-receiving portions and signal readout circuits must be formed on the surface of the same semiconductor substrate, making it impossible to raise the area of the light-receiving portions. When the area of the light-receiving portions cannot be raised, the percent utilization of light is drastically reduced. Accordingly, in the related art solid imaging device, the drop of percent utilization of light has been compensated by providing a microlens or inner lens in upper position to converge light rays into the light-receiving portions. However, such a measure has inevitable problems including an increase in light quantity loss due to optical reflection. It is said that the related art imaging devices have several tens of percentages of light quantity loss. Further, the demand for fine division of solid imaging devices has been growing more and more. Thus, a problem has arisen that when the light-receiving portions are divided more and more, the difference in angle of incidence of light between the periphery and the center of the imaging device makes difference in the percent convergence by microlens, causing shading.
Under these conditions, the configuration of the solid imaging device as described in JP-A-58-103165 has been reviewed. In accordance with this solid imaging device, light-sensitive layers are deposited on a semiconductor substrate having a signal readout circuit formed on the surface thereof. In this arrangement, these light-sensitive layers act as light-receiving portion. The photoelectric conversion signal obtained in these light-sensitive layers is read out to the exterior by a signal readout circuit. In other words, a photoelectric conversion layer-stacked structure is formed.
In this arrangement, the light-receiving portion can be provided with an aperture having a greater size, making it possible to solve the aforementioned problems. In recent years, photoelectric conversion layer-stacked solid imaging devices disclosed in JP-A-2002-83946, JP-T-2002-502120, JP-T-2003-502847, and Japanese Patent 3,405,099 have been proposed. The use of a device comprising an organic material as a photoelectric conversion layer having such an arrangement is very desirable from the following standpoints of view. The spectral wavelength of an organic material can be relatively easily adjusted by changing the structure thereof. A photoelectric conversion device comprising an organic semiconductor can be realized in a thickness on the order of 100 nm. Thus, the total thickness of the photoelectric conversion layers can be reduced even if they are deposited.
In order to further enhance the functional device comprising an organic material, etc., it is necessary the electrode on the organic semiconductor layer be finely worked. However, it is disadvantageous in that when this fine working is effected using the related art method, the properties of the functional device are remarkably deteriorated.
Thus, the functional device prepared according to the related art method is disadvantageous in that the device properties are remarkably deteriorated.